The invention relates to a connecting device for electrically connecting two circuit boards, the connecting device comprising a first and a second coaxial connector and a coupling member, wherein the two coaxial connectors and the coupling member each have an outer conductor and an inner conductor and the outer conductors of the coaxial connectors are electrically interconnected via the outer conductor of the coupling member and the inner conductors of the coaxial connectors are electrically interconnected via the inner conductor of the coupling member and wherein the coupling member is arranged between the two coaxial connectors so as to be tiltable from an axially aligned orientation and displaceable in an axial direction.
Electrical installations often use multiple circuit boards with conductive traces that must be electrically interconnected. In this regard, the circuit boards may have coaxial connectors arranged thereon, these then being connected to one another via, for example, a coaxial cable. The connection via coaxial cable is advantageous in that positional inaccuracies and relative movements of the two circuit boards can be compensated for. However, the connection using a coaxial cable is comparatively expensive and has the additional drawback that the spacings between the two circuit boards must be chosen to be relatively large.
Instead of having the coaxial connectors of the circuit boards interconnected via coaxial cable, it has been proposed that the two coaxial connectors be interconnected via a rigid coupling member. The coupling member is of substantially cylindrical configuration and makes it possible for the two circuit boards and the coaxial connectors fixed thereon to be arranged at a small spacing from one another. The coupling member has an inner conductor via which the inner conductors of the two coaxial connectors are interconnected. Furthermore, the coupling member has an outer conductor via which the outer conductors of the two coaxial connectors are interconnected. The coupling member is arranged between the two coaxial connectors and it can be tilted away from an orientation in which the coupling member is in axial alignment with the two coaxial connectors and it can be displaced in an axial direction. This makes it possible for the two circuit boards to be arranged at a small spacing from each other and to move relative to each other to a certain extent, while maintaining electrical connection therebetween. Furthermore, the tiltable and axially displaceable arrangement of the coupling member allows for positional inaccuracies to be compensated for.
A connecting device of the kind mentioned at the outset is known from German utility model number DE 202 08 425 U1. In the connecting device described therein, the coaxial connectors each have an inner conductor in the form of a contact pin which is capable of being brought into engagement with an end-face recess of the inner conductor of the coupling part. The outer conductors of the coaxial connectors each form an outer-conductor socket which can have the outer conductor of the coupling member plugged thereinto. The outer conductor of the coupling member has, at each of its ends, a surrounding annular bead which contacts the inner face of the outer-conductor socket. The known connecting device allows the coupling member to be axially displaced to a certain extent and to be tilted from an axially aligned orientation. However, there may be micromovements, in particular vibrations, of the coupling member occurring as a result of, for example, exposure to shock. The micromovements may cause abrasion, and this may impair the electric transmission properties of the connecting device.
The publication WO 00/52788 A1 proposes a connecting device in which the coupling member is mechanically connected to one of the two coaxial connectors by a fixed ball joint. While the fixed ball joint makes it possible for the coupling member to be tilted relative to the coaxial connector, it does not allow axial movement thereof with respect to said coaxial connector.
DE 100 57 143 C2 proposes a connecting device in which the coupling member is likewise mechanically connected to one of the two coaxial connectors. To this end, a radial extension arranged at the outside of the outer conductor of the coupling member latches into an annular groove arranged on the inside of the outer conductor, configured as an outer-conductor socket, of a coaxial connector. This constrains the freedom of movement of the coupling member. Furthermore, it has been shown that providing a latch connection may impair the electric transmission properties of the connecting device.
It is an object of the present invention to improve a connecting device of the generic kind such that it has improved electric transmission properties and the risk of micromovements of the coupling member can be reduced.